When you have comepleted your Sinnoh pokedex, go to stark mountain. (Before you go there,
you will meet your friend and one of the gym leaders, blah, blah, blah.)There Buck will be
waiting. Team up with him(he has a claydol) and get to the place where your friend is
standing in front of. Go in and Buck will take the Magma Stone. After that, go to the
survival area and go in one of the houses.Talk to the old man, and then Buck. He will go
and put the magma stone back. Then, return to the place he took the Magma Stone from and
Heatran will be waiting. It could be a boy or girl at lvl 70. I suggest that you save
first, and heres a little hint, get its HP low then confuse/parylize/put it to sleep or
whatever then through a couple ultra/great balls. I caught it with a little HP, it
confused, with a great ball. Good Luck!!